The present invention relates generally to a loading cam for continuously variable toroidal transmissions and more particularly, to a lubrication structure thereof.
A loading cam interposed between a cam flange and an input disk comprises cam rollers which contact the cam flange and the input disk, and a holding member for holding the cam rollers to restrict the positions thereof. The loading cam serves to press, upon shifting, the input disk to an output disk by relative rotation of the cam flange and the input disk so as to ensure frictional engagement with a power roller interposed between the two disks.
Generally, the loading cam is lubricated with oil supplied through holes formed at the base of the cam flange. When relative rotation of the cam flange and the input disk occurs, e.g. upon shifting, the cam rollers and the holes do not positionally correspond to each other, causing insufficient lubrication of the cam rollers, resulting in remarkably accelerated wear of the cam rollers and a cam surface, and possible seizure of the cam rollers.
In this connection, JP-A 2-261950 proposes a loading cam including a trough extending from the input disk to cover an end of a drive plate or cam flange or a trough connecting the drive plate and the input disk, and an oil reservoir formed inside the trough to hold lubricating oil for the cam rollers.
As for the above loading cam, engine torque transmitted to the input disk through the drive plate and the loading cam produces inevitable deformation of the input disk, which accompanies deformation of the trough. This requires an increase in space for the trough, resulting in enlarged size of the transmission, and results in possible detachment of the trough from the input disk.
It is, therefore, an object of the present invention to provide a loading cam for continuously variable toroidal transmissions which ensures lubrication of the cam rollers without any increase in size.